Compositions and methods for waterproofing wet structures formed from water-penetrable construction materials

ABSTRACT

Disclosed are waterproofing agent primer compositions which can be applied to wet and dry structures and methods of waterproofing structures made of waterpenetrable construction materials which can be used on wet and dry structures. The primer compositions include a C8-C18 fatty acid, a natural or synthetic rubber, a resin, and an organic solvent.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to compositions and methods useful forwaterproofing or dampproofing various water-penetrable materials used inbuilding construction and other civil engineering projects.Specifically, the invention relates to new primer compositions andmethods of using these compositions which eliminate the need forallowing construction materials to dry prior to applying waterproofingor dampproofing agents.

2. Description of Related Art

Various materials used in building construction and other civilengineering projects such as roads and bridges are susceptible to waterpenetration resulting either from their inherent properties orimperfections such as cracks or pores. Reducing or eliminating waterpenetration through structures formed of these materials often isdesirable, and may be critical in certain structures such as thosehousing expensive electrical equipment or tunnels moving vehicular orpedestrian traffic under bodies of water. Available waterproofing agentsinclude coal tar-based and asphalt-based compositions. Asphalt-basedcompositions are preferred; most preferred are preformed, single ormultilayer sheets of waterproofing, asphalt-based adhesives such asdescribed in U.S. Pat. Nos. 3,741,856; 3,853,682; and 3,900,102.Bituthene® brand of waterproofing membranes is an example of preferred,commercially available asphalt-based waterproofing agents.

Many currently available waterproofing agents are very effective whenapplied correctly. Correct application of currently available materials,however, requires that the structure be dry before the waterproofingagent is applied. Although waterproofing agents have been used for manyyears, for example, Bituthene® has been used for approximately 20 years,no acceptable method for applying waterproofing materials to wetstructures has been developed. Thus, inclement weather and the timerequired for curing of hydrophilic construction materials such asconcrete result in delays which increase construction costs. Therefore,there has been and remains a need for compositions and methods whichenable application of waterproofing agents to dry, wet, or incompletelycured construction materials.

U.S. Pat. No. 4,172,830 to Rosenberg et al. is one of many examples ofreferences disclosing sheet-like flexible materials used forwaterproofing.

U.S. Pat. No. 3,333,980 to McCord describes use of a very thin, orientedlayer of fatty acid deposited on the surface of water-insolubleparticles in aqueous media to render the particles hydrophobic andorganophilic. Uses attributed to the invention described in this patentare surface treatment of pigments used in paint and cosmetic manufactureand use as fillers and bonding agents in manufacture of refractories andplastics.

U.S. Pat. No. 3,936,311 to Kirst et al. describes coating materials forbuildings, which renders the buildings water-repellent, consisting ofcement and/or lime, fillers, and water which contain, as a hydrophobingadditive, 0.1-3% by weight of one or more water-soluble esters ofsaccharose and fatty acids preferably having 10-20 carbon atoms.

U.S. Pat. No. 3,625,807 to Beemer, describes an adhesive compositioncomprising a diene elastomer, for example, a butadiene-styrenecopolymer, and a fatty acid in a volatile solvent. In thesecompositions, fatty acids are included as emulsifiers.

U.S. Pat. No. 3,951,722 to Howson et al. discloses contact adhesivecompositions including a polychloroprene and saturatedhydroxy-carboxylic acid in an organic solvent.

U.S. Pat. No. 4,283,316 to Bonsignore discloses treatment ofalumina-hydrate to make its surface compatible with thermoplasticresins.

U.S. Pat. No. 4,455,146 to Noda et al. teaches human skin applicationsfor compositions including thermoplastic elastomers and higher fattyacids.

SUMMARY OF THE INVENTION

The present invention relates to compositions and methods useful forattaching waterproofing agents to water-penetrable constructionmaterials. More specifically, the present invention relates to newprimer compositions including C₈ to C₁₈ fatty acids and methods of usingthese compositions to apply waterproofing agent to constructionmaterials which may be wet, contaminated, or incompletely curedhydrophilic materials.

DETAILED DESCRIPTION OF THE INVENTION

Optimum waterproofing of structures such as buildings, bridges, roads,and tunnels requires bonds between the structure and waterproofing agentwhich endure essentially for the life of the structure. These enduringbonds are even important in applications such as subterranean basements,where the backfill would hold the waterproofing agent in place, toprevent migration along the surface of the structure of water which mayenter through damaged areas of the waterproofing agent. To achieveenduring bonds between structures and waterproofing agents, primersusually are applied prior to application of the waterproofing agent.None of the primers currently available provide sufficiently enduringbonds when applied to wet structures or structures of hydrophilicmaterials that are not yet cured.

The present invention resides in the discovery that adding certain fattyacids or combinations thereof to currently available waterproofing agentprimers results in compositions which form sufficiently strong andenduring bonds between waterproofing agents and structures even when theprimer is applied to a structure that is wet. As used herein, a wetstructure is one that has moisture on its surface, moisture containedwithin that could migrate to its surface before an applied waterproofingagent primer was completely dried, or is constructed of a hydrophilicmaterial, such as Portland cement concrete, that is incompletely cured.The fatty acids used in these compositions are fatty acids having fromabout 8 to about 18 carbon atoms and are straight-chain or branched, andmay be saturated or unsaturated. Fatty acids having an even number ofcarbon atoms are preferred. Stearic, lauric, and palmitic acids are morepreferred; myristic (tetradecanoic) acid is most preferred. The inventedcompositions contain one or more C₈ -C₁₈ fatty acids in an amountadequate to produce a sufficiently strong and enduring waterproofingagent-structure bond, determined as described below, when the primercomposition is applied to a wet structure, preferably in a concentrationfrom about 0.1% to about 3% weight-to-weight (W/W). The inventedcompositions are prepared by mixing, preferably forming a solution of,an appropriate amount of one or more C₈ -C₁₈ fatty acids with aconventional waterproofing agent primer.

Conventional waterproofing agent primers used in making the inventedcompositions generally are mixtures of natural or synthetic rubbers anddiluent or filler resins in organic solvents. The rubbers which can beused include neoprene, butyl rubber, natural rubber or,styrene-butadiene random or block copolymers with block copolymerspreferred. Other natural or synthetic rubbers useable in this inventionare those that provide sufficient primer-structure adhesion and areknown to and readily determinable by those skilled in the art. Preferredamounts of natural or synthetic rubbers are about 1% to 25%, about 12%is most preferred when the rubber is a styrene-butadiene blockcopolymer. Optionally, the included rubber can be extended by additionof any of the standard oils used to extend rubbers. The amount of oiladded is up to 66%, about 50% is preferred.

The diluent or filler resins included in the primers generally are knownto those skilled in the art and include hydrocarbon resins such ascoumarone-indene resins, polyterpenes, and aromatic petroleum resins,optionally alkylated. Asphalt also is such a resin. Nevchem®, acommercially available hardening resin, is preferred.

The organic solvents in the conventional primers used to make theinvented compositions can be any organic solvent in which the fattyacids to be used are sufficiently soluble to prepare primer compositionsof the present invention. Such solvents generally are known or readilydeterminable by standard methods and include mineral spirits, ethers,alcohols, ketones, or, preferably, xylene.

The invented compositions are used with known liquid or preformed solidwaterproofing materials based on coal tar or asphalt. Asphalt-basedwaterproofing materials are preferred. Especially preferred arewaterproofing materials constructed of preformed, multilayer, flexiblesheets including an asphalt layer and a water-impenetrable polymericfilm layer. Various flexible sheet waterproofing agents are commerciallyavailable. Bituthene® brand waterproofing membranes are preferredcommercially available waterproofing agents.

Various civil engineering structures including, for example, buildings,bridges, roads, and tunnels, are made waterproof using the presentinvention. As used herein, making a structure "waterproof" meansreducing or eliminating the ability of water to penetrate the structure.The present invention is used to make waterproof structures constructedof materials which are water-penetrable either inherently or as a resultof imperfections such as cracks or pores. The types of water-penetrableconstruction materials with which the present invention is used includewood, brick, stone, blended cements, pozzolanic cements, or concrete,preferably Portland cement concrete.

According to the presently invented methods for reducing waterpenetration through a structure, initially a primer which when appliedto a wet structure has the ability to form a sufficiently strong andenduring bond between the surface of the structure and a subsequentlyaffixed waterproofing agent is applied and allowed to dry. Thereafter, awaterproofing agent is affixed to the primer-coated structure surface.Preferred primers having the properties to form sufficiently enduringbonds between structure surfaces and waterproofing materials even whenapplied to wet structures are the presently invented compositionscontaining fatty acids.

Using the invented methods, the primer preferably is applied to astructure surface at a coverage rate of from 5 to 10 square meters perliter, more preferably 6 to 8 square meters per liter, with a final filmthickness of about 0.03 millimeters. The waterproofing agentssubsequently affixed to the primer coated structure surface either areadhesive or non-adhesive. When non-adhesive waterproofing agents areused or when it is desirable to affix a non-adhesive surface of anadhesive waterproofing agent to the primer, the primer is made tacky bystandard methods known in the art such as by using softer rubbers, usingless resin, or using more oil in the rubber. In the most preferredmethod the structure to be waterproofed is coated with a fatty acidcontaining primer and then a single or multilayer sheet of waterproofingasphalt-based adhesive, preferably a sheet having a major exposedadhesive surface and a second major exposed non-adhesive surface, suchas Bituthene® brand of waterproofing membrane, is applied so that anadhesive surface of the waterproofing agent is in contact with theprimer. In some applications, however, it may be desirable to apply suchsheets of waterproofing agents so that a non-adhesive surface of thewaterproofing agent is in contact with the primer-coated structuresurface.

The Example 3 procedure is used to determine whether a primer applied toa wet structure surface has the ability to produce a sufficiently strongand enduring bond between the waterproofing agent and structure surface.Using this test, primers applied to wet structure surfaces that at 28days produce waterproofing agent-structure bond strengths that are atleast 33% of, preferably at least 50% of, more preferably at least 66%of the bond strengths produced when applied to dry structure surfacesare defined as producing sufficiently strong and durable bonds to enabletheir use in the invention. As used herein, primers meeting thesecriteria are referred to as primers which can be used on wet and drystructures.

In making the above described invention, the inventor was surprised todiscover that the surface active properties of fatty acids aloneapparently are not the basis for their utility in primers which can besatisfactorily applied to wet structures. The inventor initially testeda variety of other surface active agents such as Pluronic L-92, Pluronic25 R-2 (both non-ionic surfactants) and Bitran H (a cationicsurfactant), and discovered that none of them when added to primersapplied to wet structures resulted in bonds between the structures andwaterproofing agents of sufficient strength and durability. As a result,although not intending to be bound to any particular mechanism by whichthe fatty acids produced the unexpected results, it is believed that thefatty acid primers are operable even when applied to wet structuresbecause the fatty acids produce a chemical bond between the structure,particularly alkaline structures such as concrete, and the primer. Thus,contemplated equivalents of the present invention are primers operablewhen applied to wet structures which contain other types of compoundswhich form chemical bonds between the structure and primer.

EXAMPLE 1 Primer Containing Myristic Acid

Myristic acid (1%) was mixed using a sonic bath into commerciallyavailable Bituthene® P-3000 primer. The composition thus preparedcontained 1% myristic acid, about 12% styrene-butadiene block copolymerextended 50% with oil, and 12% Nevchem®140 (alkylated aromaticnon-saponifiable petroleum hydrocarbon resin with softening point ofabout 140° C.) in xylene. The composition thus prepared was applied andtested according to the procedure described in Example 3, and theresults are shown in Tables I and II, below.

EXAMPLE 2 Primer Containing Stearic Acid

A composition similar to that described in Example 1 was prepared byadding stearic acid (1%) to Bituthene® P-3000 primer. This compositionalso was applied and tested as described in Example 3, and the resultsof such testing are displayed in Tables I and II, below.

EXAMPLE 3 Bond Strength Testing Procedure

The building material used in this testing procedure are porous concreteblocks (71/2 inches by 151/2 inches, by 11/2 inches thick) obtainablefrom a conventional building materials supplier. The blocks first aresaturated with water and then a paste of Type I cement is applied toproduce a uniform layer. The pasted blocks to be used in wet-surfacetesting then are cured in a 100% relative humidity environment for atleast seven days and dried before use.

For testing, the block surface is divided into 3 equivalent sections and4 grams of primer are applied to each section (6 sq. meter/liter). Dryblocks are primed and allowed 4 hours drying time. Some blocks arewetted and primed in water 1/8 inch below the block surface; also 7.6 mLof water was poured onto the surface (100 mL/sq. meter). The primed wetblock then was removed from water and allowed to dry for 4 hours.

Each section of the wet and dry primed blocks then receives two 2"×7"strips of Bituthene-3000 which are rolled 3 times with a 20.85 lbroller. The primed, wet block is submerged in water and the dry, primedblock is kept dry until bond strength is tested. At selected times bondstrength between the Bituthene® and blocks is measured using 90° angle,2"/minute tensile testing machine.

Table I shows bond strength between Bituthene® brand waterproofingmembrane and pasted block at 14 days following application to dry or wetblocks using Bituthene® P-3000 primer with or without added fatty acids.

                  TABLE I                                                         ______________________________________                                                     Bond Strength (lb./in.) - 14 days                                Fatty Acid Content                                                                           Dry         Wet                                                ______________________________________                                        1% Myristic    12.3        7.2                                                1% Myristic    13.3        9.0                                                1% Myristic    14.0        11.2                                               1% Myristic    12.0        8.8                                                1% Stearic     11.3        4.6                                                1% Stearic     11.3        3.0                                                1% Stearic     14.3        9.0                                                1% Stearic     13.5        7.5                                                None           13.3        0.3                                                None           12.8        2.4                                                None           11.0        1.7                                                None           11.8        2.0                                                ______________________________________                                    

Table II shows bond strength between Bituthene® brand waterproofingmembrane and pasted block at 14 and 28 days following application to dryor wet block using Bituthene® P-3000 primer with or without added fattyacids.

                  TABLE II                                                        ______________________________________                                                     Bond Strength (lb./in.)                                                       14 Days        28 Days                                           Fatty Acid Content                                                                           Dry    Wet       Dry  Wet                                      ______________________________________                                        1% Myristic    12.9   9.1       13.3 10.2                                     1% Stearic     12.6   6.0       12.0 8.1                                      None           12.2   1.6       12.2 1.9                                      ______________________________________                                    

Table III shows bond strength between bituthene® brand waterproofingmembrane and pasted block at 28 and 120 days following application todry or wet block using Bituthene® P-3000 primer with differentconcentrations of various straight chain, saturated fatty acids.

                  TABLE III                                                       ______________________________________                                                       Bond Strength (lb/in)                                          Fatty  Fatty Acid    28 Days     120 Days                                     Acid   Concentration (%)                                                                           Dry     Wet   Dry   Wet                                  ______________________________________                                        C.sub.6                                                                              .25           11.8    3.1   14.0  3.4                                         1.0           12.6    1.3   14.9  2.7                                         2.0           13.4    5.5   11.5  2.8                                  C.sub.8                                                                              .25           11.9    5.0   12.3  5.5                                         1.0           7.4     5.0   10.4  5.3                                         2.0           7.6     1.3   11.8  3.3                                  C.sub.10                                                                             .25           12.3    8.1   14.6  5.1                                         1.0           9.4     2.3   11.5  1.9                                         2.0           8.8     3.5   11.3  5.0                                  C.sub.12                                                                             .25           9.2     11.6  11.0  3.0                                         1.0           7.6     9.0   9.3   1.4                                         2.0           4.4     13.6  10.0  10.0                                 C.sub.14                                                                             .25           5.2     4.9   9.8   9.0                                         1.0           13.3    10.2  13.0  8.0                                         2.0           1.9     13.3  12.8  11.8                                 C.sub.16                                                                             .25           9.6     5.9   11.8  3.9                                         1.0           10.5    11.3  10.4  10.6                                        2.0           8.8     8.1   10.4  4.9                                  C.sub.18                                                                             .25           3.6     1.8   9.3   5.1                                         1.0           12.0    8.1   --    4.3                                         2.0           1.8     2.6   8.6   1.8                                  None*                10.27   2.06  11.42 2.36                                                      ±3.55                                                                              ±1.42                                                                            ±1.36                                                                            ±1.72                             ______________________________________                                         *Average of 22 for 28 days, 30 for 120 days                              

While the preferred embodiments of the invention are illustrated by theabove, it is understood that the invention is not limited to the preciseinstructions herein disclosed and the right to all modifications comingwithin the scope of the following claims and equivalents thereof isreserved.

I claim:
 1. A waterproofing agent primer composition which can be used on wet and dry structures that consisting essentially ofa C₈ to C₁₈ fatty acid; a natural or synthetic rubber; a diluent or filler resin; and an organic solvent in which the fatty acid is soluble.
 2. A waterproofing agent primer composition of claim 1 which includes about 0.1% to about 3% W/W of a C₈ to C₁₈ fatty acid.
 3. A waterproofing agent primer composition of claim 2 in which the C₈ to C₁₈ fatty acid comprises myristic, stearic, lauric or palmitic acid.
 4. A waterproofing agent primer composition of claim 3 which includes a natural or synthetic rubber selected from the group consisting of styrene-butadiene block copolymer and styrene-butadiene random copolymer.
 5. A waterproofing agent primer composition of claim 4 which includes an alkylated aromatic petroleum hydrocarbon resin.
 6. A waterproofing agent primer compositon of claim 5 wherein an organic solvent is xylene or mineral spirits.
 7. A waterproofing agent primer composition of claim 1 comprisingmyristic acid; styrene-butadiene block copolymer; an alkylated aromatic petroleum hydrocarbon resin; and xylene.
 8. A waterproofing agent primer composition of claim 7 whereinmyristic acid is present in a concentration of about 1% W/W; and styrene-butadiene block copolymer is present in a concentration of about 12%. 